• Title, Summary, Keyword: DMMP

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Supercritical water oxidation of Dimethyl methylphosphonate(DMMP) (Dimethyl methylphosphonate(DMMP)의 초임계수 산화반응)

  • Lee, Hae-Wan;Ryu, Sam-Gon;Lee, Jong-Chol;Hong, Deasik
    • Korean Chemical Engineering Research
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    • v.44 no.6
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    • pp.636-643
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    • 2006
  • Supercritical water oxidation of DMMP using continuous flow reactor was studied at temperature ranging from 440 to $540^{\circ}C$ and a fixed pressure of 242 bar. The range of residence times in the reactor was from 10 to 26 s, and oxygen excess value varied from -40 to 200%. Destruction efficiencies (DE) of DMMP were greater than 99.7% at $540^{\circ}C$, and increased as the DMMP concentrations were increased. DE of DMMP were significantly affected by oxygen concentration under stoichiometric amount, but showed little difference over stoichiometric amount. On the basis of 30 data with conversions greater than 85%, kinetic correlations for the DE of DMMP were developed. The pre-exponential factor was $(1.10{\pm}0.76){\times}10^6$, and the activation energy was $90.66{\pm}3.87kJ/mol$, and the reaction orders for DMMP and oxygen were $1.02{\pm}0.03$, $0.32{\pm}0.03$, respectively. The model predictions agreed well with the experimental data.

Influence of the Micropore Structures of PAN-based Activated Carbon Fibers on Nerve Agent Simulant Gas (DMMP) Sensing Property (PAN계 활성탄소섬유의 미세기공 구조가 신경작용제 유사가스(DMMP) 감응 특성에 미치는 영향)

  • Kang, Da Hee;Kim, Min-Ji;Jo, Hanjoo;Choi, Ye Ji;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.29 no.2
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    • pp.191-195
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    • 2018
  • In this study, the influence of microporous structures of activated carbon fibers (ACFs) on dimethyl methylphosphonate (DMMP) gas sensing properties as a nerve agent simulant was investigated. The pore structure was given to carbon fibers by chemical activation process, and an electrode was fabricated for gas sensors by using these fibers. The PAN based ACF electrode, which is an N-type semiconductor, received electrons from a reducing gas such as DMMP, and then electrical resistance of its electrode finally decreased because of the reduced density of electron holes. The sensitivity of the fabricated DMMP gas sensor increased from 1.7% to 5.1% as the micropore volume increased. It is attributed that as micropores were formed for adsorbing DMMP whose molecular size was 0.57 nm, electron transfer between DMMP and ACF was facilitated. In conclusion, it is considered that the appropriate pore structure control of ACFs plays an important role in fabricating the DMMP gas sensor with a high sensitivity.

The Effects of Flow Velocity on the Adsorption Characteristics of Organic Phosphorus Compounds

  • Kim, Chul-Sung;Lim, Jong-Sun;Baeg, Seung-Jae;Byun, Yong-Gwan
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.E
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    • pp.19-25
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    • 1998
  • Adsorption characteristics of DMMP and IMPF were investigated using dynamic adsorption method. Adsorbate vapor was forced to Pass at fixed flow rate of 4 mg/I through Cu Cr impregnated activated carbon column at several different flow velocities until the effluent concentrations exceeded 4.0$\times$10$^{-5}$ mg/I. The kinetic adsorption capacity, adsorption kinetic constant, and critical bed weight of the activated carbon were determined for DMMP and IMPF vapors by plotting breakthrough time as a function of carbon weight. A mathematical expression was deduced from our experimental data to represent the relationships between kinetic adsorption capacity and flow velocity. According to our experimental results, the lifetime of DMMP was longer than that of IMPF under the same conditions. Their relationship can be expressed empirically as follows: Tb(DMMP) = 0.9825$\times$Tb(IMPF)-15.368

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Effects of Additives on the DMMP Sensing Behavior of SnO2 Nanoparticles Synthesized by Hydrothermal Method

  • Kim, Hong-Chan;Hong, Seong-Hyeon;Kim, Sun-Jung;Lee, Jong-Heun
    • Journal of Sensor Science and Technology
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    • v.20 no.5
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    • pp.294-299
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    • 2011
  • $SnO_2$ nanoparticles were synthesized by a hydrothermal method and gas sensors were fabricated using nanoparticles to detect dimethyl methylphosphonate(DMMP) gas. The prepared $SnO_2$ nanoparticles exhibited a high response(72 at $500^{\circ}C$) to 5 ppm DMMP gas compared to commercial $SnO_2$ nanopowders, but their recovery was relatively poor. Various metals(Ni, Sb, Nb) were added to the $SnO_2$ nanoparticles to improve their recovery properties. The focus of this study was to investigate the effects of metal oxide additives on DMMP sensing behavior in $SnO_2$ nanoparticles.

Effect of Hydrophobic Coating on Silica for Adsorption and Desorption of Chemical Warfare Agent Simulants Under Humid Condition

  • Park, Eun Ji;Cho, Youn Kyoung;Kim, Dae Han;Jeong, Myung-Geun;Kim, Young Dok
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.148.2-148.2
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    • 2013
  • We prepared hydrophobic PDMS-coated porous silica as pre-concentration adsorbent for chemical warfare agents (CWAs). Since CWAs can be harmful to human even with a small amount, detecting low-concentration CWAs has been attracting attention in defense development. Porous silica is one of the promising candidates for CWAs pre-concentration adsorbent since it is thermally stable and its surface area is sufficiently high. A drawback of silica is that adsorption of CWAs can be significantly reduced due to competitive adsorption with water molecule in air since silica is quite hydrophilic. In order to solve this problem, hydrophobic polydimethylsiloxane (PDMS) thin film was deposited on silica. Adsorption and desorption of chemical warfare agent (CWA) simulants (Dimethylmethylphosphonate, DMMP and Dipropylene Glycol Methyl Ether, DPGEM) on bare and PDMS-coated silica were studied using temperature programed desorption (TPD) with and without co-exposing of water vapor. Without exposure of water vapor, desorbed amount of DMMP from PDMS-coated silica was twice larger than that from bare silica. When the samples were exposed to DMMP and water vapor at the same time, no DMMP was desorbed from bare silica due to competitive adsorption with water. On the other hand, desorbed DMMP was detected from PDMS-coated silica with reduced amount compared to that from the sample without water vapor exposure. Adsorption and desorption of DPGME with and without water vapor exposing was also investigated. In case of bare silica, all the adsorbed DPGME was decomposed during the heating process whereas molecular DPGME was observed on PDMS-coated silica. In summary, we showed that hydrophobic PDMS-coating can enhance the adsorption selectivity toward DMMP under humid condition and PDMS-coating also can have positive effect on molecular desorption of DPGME. Therefore we propose PDMS-coated silica could be an adequate adsorbent for CWAs pre-concentration under practical condition.

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Effects of Oxygen Functional Groups introduced onto Activated Carbon Fibers on Gas Sensing Property of Chemical Warfare Agent (활성탄소섬유에 도입된 산소작용기가 유독성 화학작용제 감응특성에 미치는 영향)

  • Kim, Su Hyun;Kim, Min-Ji;Song, Eun Ji;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.30 no.6
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    • pp.719-725
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    • 2019
  • In this study, activated carbon fibers were treated with oxygen plasma to investigate gas sensing properties of the dimethyl methylphosphonate (DMMP), which is a simulant gas of the chemical warfare agent, according to oxygen functional group contents. As the flow rate of oxygen plasma treatment increased, oxygen groups were introduced to the surface of activated carbon fibers from 6.90 up to 36.6%, increasing the -OH group which influences the DMMP gas sensing properties. However, as the flow rate of oxygen plasma increases, the specific surface area tends to decrease because etching on the surface of activated carbon fibers occurs due to active species generated during the oxygen plasma treatment. The resistance change rate of the DMMP gas sensor increased from 4.2 up to 25.1% as the oxygen plasma treatment flow rate increased. This is attributed to the hydrogen bonding between DMMP gas and introduced hydroxyl functional group on activated carbon fibers by the oxygen plasma treatment. Therefore, the oxygen plasma is considered to be one of the important surface treatment methods for detecting chemical warfare agents at room temperature.

Research about Chemical-Biological Protection Capability of Selectively Permeable Membrane Materials Based on Polyvinyl Alcohol (폴리비닐알코올 기반 선택투과막 재료의 화생방호성능 연구)

  • Kang, Jae-Sung;Seo, Hyeon-Kwan;Kwon, Tae-Geun;Park, Hyen-Bae;Lee, Hae-Wan
    • Membrane Journal
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    • v.23 no.3
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    • pp.237-244
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    • 2013
  • We fabricated several composite membranes with selectively permeable performance designed to facilitate water vapor transport and resist DMMP vapor permeation. Materials for selective permeable membrane were based on polyvinyl alcohol and functional polymer containing basic functional group. With these materials, we characterized selectively permeable performance to identify next-generation material with chemical-biological protective capability. Results showed that polyvinyl alcohol (PVA)/polyethyleneimine (PEI) materials possessed performance with superior water vapor permeation ($2,200{\sim}2,900g/m^2/day$) and protective capability against DMMP vapor ($47g/m^2/day$).

A Study on Processes and Performance Evaluation for IR Camouflage Printed Selectively Permeable Membrane Fabrics (위장 날염된 선택 투과성 화생방 직물의 제조 공정연구 및 성능평가)

  • Jeong, Yong-Kyun;Moon, Sang-Hyun;Kang, Jae Sung;Seo, Hyeon Kwan;Park, Hyen Bae
    • Textile Coloration and Finishing
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    • v.26 no.1
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    • pp.13-21
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    • 2014
  • The object of this research is to perform the basic research for the development of selectively permeable membrane fabrics which is suitable for korean military in sense of embattlement. As a key factor of selectively permeable membrane fabrics which is suitable for korean military, this study selected the best PVA thickness and membrane selection for DMMP protection, pre-treatment method for conformational stability of face fabric and water/oil repellent process condition. Especially as the PVA coating thickness of the fabrics increase, peneration of DMMP decrease including water vapor permeation is lower. This study shows how physical features and permeability of chemical agents can be influenced by pre-treatment methods, the selection of selectively permeable membrane, the thickness of PVA etc. Results showed that outer shell / PVA / e-PTFE materials possessed performance with superior water vapor permeation (Over $3,000g/m^2/day$) and protective capability against DMMP vapor ($0.6{\mu}g/cm^2{\cdot}16hr$).

Chemiresistive Gas Sensors for Detection of Chemical Warfare Agent Simulants

  • Lee, Jun Ho;Lee, Hyun-Sook;Kim, Wonkyung;Lee, Wooyoung
    • Journal of Sensor Science and Technology
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    • v.28 no.3
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    • pp.139-145
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    • 2019
  • Precautionary detection of chemical warfare agents (CWAs) has been an important global issue mainly owing to their toxicity. To achieve proper detection, many studies have been conducted to develop sensitive gas sensors for CWAs. In particular, metal-oxide semi-conductors (MOS) have been investigated as promising sensing materials owing to their abundance in nature and excellent sensitivity. In this review, we mainly focus on various MOS-based gas sensors that have been fabricated for the detection of two specific CWA simulants, 2-chloroethyl ethyl sulfide (2-CEES) and dimethyl methyl phosphonate (DMMP), which are simulants of sulfur mustard and sarin, respectively. In the case of 2-CEES, we mainly discuss $CdSnO_3-$ and ZnO-based sensors and their reaction mechanisms. In addition, a method to improve the selectivity of ZnO-based sensors is mentioned. Various sensors and their sensing mechanisms have been introduced for the detection of DMMP. As the reaction with DMMP may directly affect the sensing properties of MOS, this paper includes previous studies on its poisoning effect. Finally, promising sensing materials for both gases are proposed.

Fabrication of DMMP gas sensor based on $SnO_2$ (산화주석을 기반으로 한 DMMP 가스센서 제작)

  • Choi, Nak-Jin;Ban, Tae-Hyun;Baek, Won-Woo;Lee, Woo-Suk;Kim, Jae-Chang;Huh, Jeung-Soo;Lee, Duk-Dong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.942-945
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    • 2003
  • Nerve gas sensor based on tin oxide was fabricated and its characteristics were examined. Target gas was dimethylmethylphosphonate($C_3H_9O_3P$, DMMP) that is simulant gas of nerve gas. Sensing material was $SnO_2$ added ${\alpha}-Al_2O_3$ with $4{\sim}20wt.%$ and was physically mixed. And then it was deposited by screen printing method on alumina substrate. Sensor device was consisted of sensing electrode with interdigit(IDT) type in front and heater in back side. Total size of device was $7{\times}10{\times}0.6mm^3$. Crystallite size of fabricated $SnO_2$ were characterized by X-ray diffraction(XRD, Rigaku) and morphology of the $SnO_2$ powders was observed by a scanning electron microscope(SEM, Hitachi). Fabricated sensor was measured as flow type and sensor resistance change was monitored real time using LabVIEW program. The best conditions as added $Al_2O_3$ amounts and operating temperature changes were 4wt.% and $300^{\circ}C$ in DMMP 0.5ppm, respectively. The sensitivity was over 75%. Response and recovery times were about 1 and 3 min., respectively. Repetition measurement was very good with ${\pm}3%$ in full scale.

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